title: Rectangular loop-gap resonator with the light access to the sample.
abstract: A modified rectangular loop-gap resonator for X-band electron paramagnetic resonance (EPR) studies of aqueous samples, enabling the light access, is described. Changes introduced into rectangular resonator geometry, previously presented in Piasecki et al. (1998) [1], and redesigned coupling structure lead to the better thermal and mechanical stability. The modified structure makes provision for the controlled light access to the sample placed in a flat cell during an EPR experiment. The sensitivity of the resonator for aqueous samples as well as an experimentally tested microwave magnetic field homogeneity are presented. Results of simulations and experimental tests indicate that the presence of light access holes in the resonator's front side does not disturb the uniformity of microwave magnetic field distribution in the nodal plane. The optimal flat cell thickness for unsaturable and saturable aqueous samples has been calculated for this new structure. A modified rectangular geometry of the loop-gap resonator ensures a good performance for aqueous samples allowing its convenient and efficient light illumination during EPR signal recording .
authors.affiliation: Department of Biophysics, Jagiellonian University, Gronostajowa, Kraków, Poland. Malgorzata.Dutka@uj.edu.pl
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Dutka
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Oleś
authors.forename: Marek
authors.initials: M
authors.lastname: Mossakowski
authors.forename: Wojciech
authors.initials: W
authors.lastname: Froncisz
mesh_terms: D004574:Electromagnetic Fields; D004578:Electron Spin Resonance Spectroscopy / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D008029:Lighting / Q000379:methods; D008872:Microwaves; D011487:Protein Conformation; D012996:Solutions / Q000737:chemistry; D013113:Spin Labels
chemical_list: D012996:Solutions; D013113:Spin Labels